Protein Associated with Poor Breast Cancer Prognosis
High levels of the Ki-67 protein are associated with poor prognosis in early breast cancer patients, but it may not able to predict which patients will benefit from additional chemotherapy.
The percentage of proliferating cells in a tumor is a predictor of breast cancer prognosis. The level of Ki-67 expression is sometimes used as a measure of cell proliferation. Some studies have suggested that breast tumors with a high percentage of cells expressing Ki-67 are more responsive to chemotherapy.
Giuseppe Viale, M.D., of the University of Milan in Italy and colleagues at the International Breast Cancer Study Group conducted research to determine whether Ki-67 expression could predict responsiveness to chemotherapy given after breast cancer surgery. They assessed Ki-67 expression in tumor samples taken from patients in two randomized clinical trials that compared endocrine therapy given after chemotherapy with endocrine therapy alone.
The researchers found that Ki-67 expression did not predict which women would benefit from chemotherapy prior to endocrine therapy. However, having a high percentage of cells expressing Ki-67 was associated with poorer disease-free survival.
“In this study, Ki-67 [expression] was a prognostic factor, not a predictive factor,” the authors write.
In an accompanying editorial, Matthew Ellis, Ph.D., of Washington University in St. Louis notes that these results support the position of the American Society of Clinical Oncology Tumor Markers Expert Panel that Ki-67 should not be used the make decisions about chemotherapy.
“Biomarker studies with negative results can be just as important to publish as those with positive results…because clinging to a long-favored but incorrect hypothesis in the face of negative evidence impedes scientific and clinical progress,” Ellis writes.
No Link Found Between Personality Traits and Cancer Risk
Personality traits do not appear to be associated with breast cancer risk.
Previous studies have linked personality traits with cancer risk. In 1996, Eveline Bleiker, Ph.D., of The Netherlands Cancer Institute and colleagues found a weak association between the development of breast cancer and antiemotionality—a lack of emotional behavior or trust in one’s own feelings. No other personality traits were associated with breast cancer risk in this study.
The researchers conducted a follow-up study with the same group of about 9,700 women who had previously completed a survey that assessed personality traits such as anxiety, anger, antiemotionality, optimism, understanding, and emotional expression. In addition to looking at individual personality traits, the researchers examined how interactions between personality traits influenced breast cancer risk.
Of the women who completed the questionnaire, 217 were diagnosed with breast cancer during the 5- to 13-year follow-up. The researchers did not find any personality trait or personality profile that was associated with increased breast cancer risk.
“We could not confirm our previously reported association between antiemotionality and breast cancer. Our finding that no psychological risk profile was associated with the incidence of breast cancer may help oncologists to reassure patients that their personality appears to have played no role in the development of their breast cancer,” the authors write.
Contact: Danielle Cardozo, Netherlands Cancer Institute, +31 20 512.2867, firstname.lastname@example.org
Pathology Reports Acceptable for Determining ER Status in Breast Cancer Trials
Pathology reports offer a fairly accurate alternative to repeated testing in a central laboratory for determining estrogen receptor status in large epidemiologic studies of women with breast cancer.
When conducting epidemiologic studies of breast cancer patients, researchers often use pathology reports to obtain estrogen receptor status instead of testing them again in a central laboratory, which can be impractical. But it was unknown whether these original pathology reports were accurate or not, and misclassification of estrogen receptor status could have a serious impact on the results of a study.
Laura Collins, M.D., of Beth Israel Deaconess Medical Center in Boston and colleagues assessed the reliability of estrogen receptor results from pathology reports by comparing them with immunohistochemical tests that they had performed by a central laboratory.
The pathology reports and the later tests were the same for 1,615 of the 1,851 samples (87.3 percent). The authors concluded that there was a high rate of agreement between the pathology reports and the central laboratory tests.
“Our findings, therefore, indicate that using [estrogen receptor] assay results from pathology reports is a reasonable alternative to using central laboratory testing to obtain [estrogen receptor] results in large, population-based studies of women with breast cancer,” the authors write.
Contact: Bonnie Prescott, science writer, Beth Israel Deaconess Medical Center, (617) 667-7306, email@example.com
Sorafenib Shows Potential for Treating Some Forms of Leukemia
The drug sorafenib, which is used to treat kidney and liver cancer, may be effective acute myeloid leukemia patients with specific gene mutations.
Previous studies have shown that sorafenib is especially effective against acute myeloid leukemia cells that have certain mutations known as internal tandem duplication (ITD) mutations of the Fms-like tyrosine kinase 3 (FLT3) gene.
Michael Andreeff, M.D., Ph.D., of the University of Texas M. D. Anderson Cancer Center in Houston and colleagues examined sorafenib’s ability to kill leukemia cells that express either the common form or mutant copies of FLT3. They also gave sorafenib to mice bearing leukemia cells with known FLT3 gene mutations and to leukemia patients with and without the mutations.
The researchers found that sorafenib slowed growth and induced cell death in the FLT3 mutant leukemia cells and increased survival of the mice with FLT3 mutant leukemia. Sorafenib reduced the percentage of leukemia cells in blood and marrow in patients with this mutation, but not in patients without the mutation.
“Our findings imply that sorafenib is a potent antileukemic agent in patients with FLT3-ITD mutant [acute myeloid leukemia], a form of [the disease] that responds poorly to traditional chemotherapy,” the authors write.
Contact: Scott Merville, M. D. Anderson Cancer Center, (713) 792-0661, firstname.lastname@example.org
Also in January 29 JNCI:
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